Currently, along with the advancement and spreading of cloud technology, the environment of use of IT platform is advanced from a conventional system in which a user comprehends the status of use and constructs the system environment to a case outsourcing the system including the construction of the environment of use to external venders (adopting of a cloud system). On the other hand, along with the rapid increase of electronic data handled in businesses and in personal life in a so-called information society, the enlargement of storage capacity and the increase in scale of the information system accompanying the same has caused a drawback such as complex operation due to the complication of the backup environment.
Therefore, in order to release the users from the complication of system management, the adoption and enhancement of outsourcing of information systems using a cloud system is adopted and enhanced. On the other hand, the tendency to emphasize the used data capacity that occupies a large portion of the costs is increasing at the user side or the cloud provider side. Further, there is a need in the cloud provider side to precisely comprehend the storage capacity being actually used including the allocated storage capacity and the backup capacity in a storage system recognized by the OS of the server, from the viewpoint of appropriation of system allocation costs.
In other words, storage capacity has rapidly increased by the advancement of cloud technology, and along therewith, there are expanding needs for performing backup of the storage subsystem. Therefore, in order to operate the backup processing, it is important to comprehend the amount of actually used storage capacity per user, from the viewpoint of system operation, maintenance and planning.
Patent literature 1 discloses an art related to the above-described technique, teaching a method for managing data in a storage system performing backup.